Does your master cylinder have an integral fluid revervoir? I suspect that it will have.
Without knowing the specifics of your set-up, I suspect that your 'long' pedal is due to the kick-back associated with your rear disks.
I have dual master cylinders with balance bar adjustment. The cylinders are Girling cylinders of different bore size to get the front/rear balance close. The balance bar is for fine tuning for dry and wet braking.
I suggest that you approach a Morgan specialist with race car set-up experience. Alternatively, you can PM me for details of my car's spec, etc.
